1. Technical Field
The present invention relates to a gel actuator and a gel used for the same.
2. Related Art
Since a gel made of polyvinyl chloride (PVC) has an action that it is deformed when an electric field is applied, an actuator using the behavior is proposed.
FIGS. 11A and 11B illustrate a bending action of a flexible gel actuator. FIG. 11A illustrates a state where a positive electrode 6a and a negative electrode 6b are disposed on both sides of a gel 5 formed in a flat plate shape so that one end side of the gel 5 extends from the electrode ends. FIG. 11B illustrates a state where voltage is applied between the positive electrode 6a and the negative electrode 6b. 
When voltage is applied between the positive electrode 6a and the negative electrode 6b, electric charges are injected from the negative electrode 6b into the gel 5, the electric charges moved to the positive electrode 6a side are accumulated in the positive electrode 6a and a portion near the positive electrode 6a before being discharged, and the action of making the gel 5 electrostatically adhered near the positive electrode 6a is made.
Deformation of the gel 5 is not simple bending but is induced by creep deformation and is deformation that the gel 5 is concentrated at the end portion of the positive electrode 6a. When the electric field is eliminated, the electric charges are discharged, the action that the gel 5 is adhered to the positive electrode 6a is lost, and the gel 5 returns to the original state by its intrinsic elasticity (FIG. 11A). Since the bending deformation occurs accompanying the application of voltage and the cancellation of the application of voltage, an actuator can be formed by using the deformation action.
FIGS. 12A and 12B illustrate an action when a mesh-state electrode is used as a positive electrode 7a and voltage is applied between a negative electrode 7b disposed on the under face of the gel 5 and the positive electrode 7a. FIG. 12B is a state where voltage is applied. When voltage is applied, the gel 5 enters gaps in the mesh of the positive electrode 7a by creep deformation. Since the gel 5 enters the gaps, the gel actuator becomes thinner as a whole. When the application of the voltage is stopped, the gel 5 returns to the original state. By performing the application of the voltage between the positive electrode 7a and the negative electrode 7b and cancellation of the application as described above, the action that the gel actuator expands and contracts as a whole in the thickness direction is made. Consequently, the actuator can be constructed by using the expansion/contraction action.